Auto insert rows macro required

[needhelp2]

Hi,

I want to know that how i can insert rows after specifice selection

e.g i have two values in drop down menu in b4. Insert-1,Insert-2
if insert-1 selected from drop down then there is no need to insert but if insert-2 selected then three rows after (b10).

I think its done by macros can any one assist me to do so?

Best Regards,
Rob

and each three rows contain vales in b10,b11,b12,SKU,PO,TPPO respectively